When developing software you want to achieve a high level of code quality. Part of the quality is a result of good preparations before development. Most software projects start with a software architecture. When we talk about software evolution we usually talk about the way the code changes during the entire development process. We focus on the implementation and not the preparation.

This means we look at developers, how they implement the system and how this system changes during the development. This means we calculate software metrics, some of them are Lines of Code (LoC), Cyclometic Complexity, code density and more. The Software Improvement Group, from now on SIG, is one of the companies that evaluates code and determins the quality of the code by some of these metrics. They use their Maintainability Model \textbf{\cite{MM}}.

Architectures are often written in the Unified Modeling Language, from now on \textbf{UML}. During the development of the software system to be the architecture also evolves to be a proper representation of the software system.

In this paper we will discuss some architecture metrics and why you should calculate these on the architecture.